#152 Processes stuck in I/O after transparent CFS failover

v1.9.1
closed-fixed
Filesystem (49)
5
2010-03-13
2008-03-25
Roger Tsang
No

Processes or threads doing I/O during transparent CFS failover get stuck waiting in I/O. They cannot be interrupted. If they are part of a thread group zombies can also appear.

How to reproduce: Start reading a large file on a CFS hard mount on the surviving OpenSSI node and force CFS to transparently failover. The application on the surviving OpenSSI node is expected to continue uninterrupted and finish reading the entire file, but instead gets stuck waiting in I/O.

Discussion

  • Roger Tsang

    Roger Tsang - 2008-03-25

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    This is a CFS super block rebuild flush race with CFS async code where down requests being flushed are asynchronously pushed back into the list of down requests. These requests have the page lock.

    Fixed in 2.0.0pre3.

     
  • Roger Tsang

    Roger Tsang - 2008-03-25

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    NB: This bug might not manifest in the earlier 1.9.x releases because the CFS rebuild thread is RT before (around) 1.9.3.

     
  • Roger Tsang

    Roger Tsang - 2008-07-04
    • status: open --> open-later
     
  • Roger Tsang

    Roger Tsang - 2008-07-04

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    Fixed but not yet in code repository.

     
  • Roger Tsang

    Roger Tsang - 2009-10-27

    checked-in final fix

     
  • Roger Tsang

    Roger Tsang - 2009-10-27
    • status: open-later --> open-fixed
     
  • Roger Tsang

    Roger Tsang - 2010-03-13
    • status: open-fixed --> closed-fixed
     

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